Blasting process



' D. FERRELL El' AL 4 Mmh 17, 1936.

BLASTING PROCESS Filed Aug. 25, l19355 Patented Mer. 417, i936 ris'rizls'r oFFlcs 2,034.5 nnss'rmeraocsss nent reuen, Carterville, and Arthur w. Helmholtz. Harrisburg, lll.

Application sume 2s, 193s, serai No. essere 1 calm. (ci. 1oz- 5) A Our invention relates to the blasting' of coal or other material `and contemplates improvements Aineitisting processes and apparatus. The principal object ofthe inventionis to increase the eilectiveness of blastingV processes and apparatus. The invention is applicable tothose methods and apparatus wherein thermal explosives, such as powder and dynamite, are used and also to those methods and apparatus wherein the blasting medium. such as air, carbon dioxide and the like,

is confined in a cartridge or other receptacle and released therefrom by rupture of the container dueto the pressure of the medium therein or by mechanical, hydraulic, electrical or other means. The invention consists principally in placing the coal body or other material in a state of strain by forcing into it a fluid, gas or mud stream under sufiicient pressure to set up the desired strain. The pressure building medium is applied to the body through the drill hole in which the blasting agent is placed. 'Ihe initial pressure fills up all ilssures, laminations and cracks j in the vicinity of the drill hole and buildsup a strain which greatly/increases the effectiveness.

of the main blasting operation.

We are aware that it has heretofore been posed to mine coal and the like by pumping. wa-l ter or other liquid or fluid in@ .the coal body for the purpose of breaking it .up.V However, such processes cannot be eil'ectivefdue 'unavoldr nations inthe body. Our process, therefore.v contemplates able loss of pressure in the voids .and

merely 4thevbuilding up of lpressure in the vicinity of the drill hole to a point where leakage through the 'ore body makes higher pressure impracticabie such initial pressure and strain greatly increasing the eil'ectiveness of the main blasting operation. r I

The invention further consists in 'the blasting process and apparatuain the, parts and combinations and arrangements of parts and in the sequence of operations hereinafter described. In the accompanying drawing, Fig. 1 is a diagrammatic sectional view through `a portion of a coal body and through a blasting cartridge embodying our invention;

.'lilg.2isasimilarviewofamoditledconstruc tion; and

Fig. 3 is a similar view showing an embodiment using a thermal explosive. l Y i Referring to Fig. 1,. a recess .Als drilled into a body of coal B, in which ilssures or crevices C are indicated. Mounted in the drill hole A is a blasting cartridge D and the end of the drill hole inclosed by a suitable plug E. The cartridge D is provided at one end with a threaded bore i in which is received a y.threaded'nut 2. Against this nut is mounted a disk I of comparatively wealrmaterial and a retaining nut 4 is mounted in the extreme end of the cartridge against said disk. Extending through the plug Ijis a line 5 for supplying air or other gas or v liquid under pressure, said line being connected with the end of the cartridge and a passageway 6 communicating with said supply line and with i5 the interior of the cartridge. When the pressure in the cartridge is built up to a sumcient point, the disk is .broken and the released pressure breaks up the coal body.

Our invention builds up an initial strain in the coal body to intensify the effect of the blasting operation. In the construction shown in Fig. 1, the end of the blasting cartridge D opposite the pressure inlet is provided with a valve body in lwhich is mounted a suitable bleeder valve l. Thus. a portion of the pressure medium entering the cartridge passes through said valve and builds up pressure and strain in the surrounding coal body. By the time-the disk 3 is broken, asa part of the main blasting op-V eration, a considerable pressure has been built up in the surrounding coal body 'and the eilectiveness .of the blas ing Voperation is greatly in- L. creased.

In the construction shown in Pig.2. a simple'il cartridge D' is used which is entirely closed except for a connection with the main pressure Vsupplyline 5a. Aseparate pressure linel with a suitable control valve 9 extends through the drill hole plug E' so that pressure may be built 80 up in the coal body. This second pressurel niedium may bethe same as that used for the main blasting operation, or it may be .water or any other suitable fluid.

Fig. 3 shows a dynam cartridge D" of com- 85 mon design and a pres line la for building up pressure in the coal body.A The dynamite is discharged after suitable pressure has been built lup.

The above described process vand 'apparatus 40 greatly increase the effectiveness of blasting nperations, and are simple and comparatively inexpensive. yObviously any desired means may be employed for the main blasting operation and many means are available for building up the ini- 46 tial pressure. Acco the foregoing description should be regarded as illustrative and we do not fwish to be limited to the precise details shown. i

What we claim is: v

The process of blasting which compris providing an opening in the body. to be blasted. in-l serting a blasting cartridge into said opening.

.plugging the end of'said opening and then forcing, fluidA under pressure through said opening into the surrounding body and building up pressure in said'body prior to operating the blasting cartridge.

DENT FERRELL. ARTHUR W. HELMHOL'IZ. 

